Field of the Invention
The present invention relates to a duct that has a sound absorbing function and a method of manufacturing the same.
Description of the Related Art
Conventionally, as this type of a duct, a duct is known in which a pair of groove-shaped members formed of a sound absorbing sheet is arranged such that groove openings are opposed to each other and in which a pair of flange portions extended outward from the groove opening edges of the pair of groove-shaped members is crimped and joined (see, for example, Patent Literature 1). Such a duct can be obtained by overlaying a pair of sound absorbing sheets, crimping the outer edge portions of the pair of sound absorbing sheets, and vacuum molding or pressure molding each of the sound absorbing sheets into a groove shape.